"This study focuses upon the annual number of births over the interval 1950-1974. Three important factors are isolated which are associated with births; these are, income, population size, and expenditures on birth control technology. Other variables inserted into the estimating equations were found to add little by way of forecasting improvements. Changes in contraceptive technology seem to be important in determining births. The increase in the power of the technology has made it feasible for households to more realistically examine children in the framework postulated by the Chicago School, Leibenstein, or Easterlin."